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Reduced replication capacity of influenza A(H1N1)pdm09 virus during the 2010–2011 winter season in Tottori, Japan
Author(s) -
Tsuneki Akeno,
Itagaki Asao,
Tsuchie Hideaki,
Tokuhara Misato,
Okada Takayoshi,
Narai Sakae,
Kasagi Masaaki,
Tanaka Kiyoshi,
Kageyama Seiji
Publication year - 2013
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.23700
Subject(s) - virus , biology , influenza a virus , virology , incubation , inoculation , viral replication , h1n1 influenza , zoology , veterinary medicine , medicine , covid-19 , immunology , disease , infectious disease (medical specialty) , biochemistry
Abstract A novel swine‐origin influenza A(H1N1)pdm09 virus has been circulating in humans since March–April, 2009. The 2009–2010 epidemic involved predominantly a single subtype of A(H1N1)pdm09 (at 96%, 46/48) in the sentinel sites of this study. However, A(H1N1)pdm09 started to circulate together with other type/subtype (49%, 33/68) at the first peak in the next epidemic season in 2010–2011: A(H1N1)pdm09/A(H3N2) (9%, 6/68), A(H1N1)pdm09/B (35%, 24/68), and A(H1N1)pdm09/A(H3N2)/B (4%, 3/68). Single infection of A(H1N1)pdm09 became a rare event (8%, 5/65) at the second peak of the same season in 2010–2011 compared with that at the first peak (50%, 34/68). Concurrently with this decline, single infections of others, A(H3N2) or B, became evident (6%, 4/65; 14%, 9/65, respectively). Triple infections were more common (29%, 19/65) at the second peak than at the first peak (4%). The A(H1N1)pdm09 detected in 2010–2011 produced less virus upon 72 hr of incubation in vitro after the inoculations at 10 4 and 3,300 copies/ml (2.3 × 10 9 and 2.3 × 10 9 copies/ml on average) than that in 2009–2010 (3.7 × 10 9 and 1.3 × 10 10 copies/ml on average; P < 0.05 by ANOVA test), respectively. As described above, the replication capacity of A(H1N1)pdm09 seems to have deteriorated in the 2010–2011 season presumably due to substantial herd immunity and allowed the existence of other type/subtype. These results suggest that assessment of replication capacity is indispensable for analysis of influenza epidemics. J Med. Virol. 85:1871–1877, 2013 . © 2013 Wiley Periodicals, Inc.